Isolators provide electrical isolation between circuits which communicate with each other. In some situations, circuits which communicate with each other operate at different voltages, for instance one at a relatively high voltage and the other at a relatively low voltage. In some situations, the circuits are referenced to different electrical ground potentials, such that a voltage in one of the circuits differs from a voltage in the other circuit. Isolators are used to electrically isolate a first circuit, operating in a relatively high voltage domain, from a second circuit, operating in a relatively low voltage domain, or to electrically isolate circuits referenced to different ground potentials. An isolation barrier is proved between the two circuits to prevent undesirable voltage cross-over. The isolator provides communication across the isolation barrier.